Q: I am running a Windows Server 2008, with IIS 7. I have installed MS FTP 7.5 and configured on the server to support Passive mode. In the configuration on MS FTP there is the ability to configure the firewall Data Channel Range. See this link for more info. http://learn.iis.net/page.aspx/309/configuring-ftp-firewall-settings/
How can i configure my Vigor2820n to dynamically open these ports when required for Passive FTP Connection ??

A: We believe that the router’s built-in function, which is called FTP ALG, will work for this scenario. As long as you are using the standard FTP port 21, the FTP service behind the router will work well if a port redirection rule for port 21 is configured. The router will modify the information contained in Control Channel, and open the data connection ports for the client automatically.
If you are not using port (TCP 21), the FTP ALG won’t work. So you will need to use the standard port first. Also check that the router’s own FTP management port is modified to another value. FTP ALG is an “always enabled” feature, which cannot be disabled.